Interrelations among the acoustic features of cries: How many features do we need?

The present study used factor analysis and multidimensional scaling to explore the dimensions underlying the acoustic features of human infants' cries. Results indicated that between two and four components account for the correlations among acoustic features. Further, features which apparently represent respiratory processes were distinct from those representing resonances of the vocal tract. There was, however, a closer relation among respiratory and glottal processes than predicted by current models of cry production. Finally, two different approaches to acoustic analysis are outlined, one which may be useful in diagnosing health problems of infants and another which may be useful in relating cry acoustics to perception and to social interactions.